The present disclosure provides a one-piece optical fiber adapter that includes a main body and a hook member. At least one first stop block is positioned on the first wall and at least one second stop block is positioned on the third wall. Two first hooks extend respectively from the second and fourth walls toward a direction of the second opening of the accommodation room. The hook member is positioned within the accommodation room of the main body and includes two second hooks, at least one third hook and at least one fourth hook. The third and fourth hooks extend respectively from the fifth and seventh walls toward a direction of the fourth opening of the accommodation room of the hook member to hook on to the first and second stop blocks, respectively.